Method and Apparatus to Lower Cost Per Watt with Concentrated Linear Solar Panel

Abstract

The present invention proposes a hybrid methodology and apparatus between photovoltaic (PV) and concentrated photovoltaic (CPV) solar panels to lower the photovoltaic solar energy production cost. In particular, the disclosed methodology addresses a simple quasi-parabolic trough PV (QPTPV) low concentration system with greater tolerance to tracker pointing errors. The quasi-parabolic trough (QPT) reflector is defocused to cover the width of a linear solar cells array, which is reduced from a large rectangular solar cells panel. In summary, the QPTPV system consists of low cost quasi-parabolic reflectors, a compact linear PV cells array and a lower cost relaxed pointing 2-axes tracker. The combination of these low cost technologies disclosed can achieve the lowest cost per kilowatt hour of photovoltaic energy production.

1 . A quasi-parabolic trough photovoltaic (QPTPV) solar energy apparatus comprising:
 multiple quasi-parabolic trough (QPT) reflectors mounted in the same orientation on the frame of a 2-axes solar tracker; and   multiple linear solar cells arrays consist of serial connected PV solar cells; wherein each of said linear solar cells array is boxed in a rectangular linear solar panel; and wherein said linear solar panel is attached to said tracker frame via two adjustable height mounting arms on both ends, and wherein said mounting arms are perpendicular to said linear solar panel and said tracker frame; and wherein each said linear solar cells array face said QPT reflector at the focal distance approximately;   wherein a linear passive radiator, or an active coolant linear flat pipe is attached to the back of each said linear solar cells array and secured inside said linear solar panel for heat dissipation; and   wherein said QPT reflectors focus on and concentrate solar rays on said solar cells arrays to produce photovoltaic power and, optionally, to produce heated water.   
     
     
         2 . The QPTPV apparatus of  claim 1  wherein said QPT reflector is made from a flat sheet of mirror reflector bended into desired parabolic curve by a QPT forming technique; wherein said QPT forming technique consists of 1) the linear span of said bended reflector matches closely to said parabolic curve linear span; 2) said reflector sheet width matches closely to said parabolic curve length between said linear span; 3) the mounting beams of said bended reflector sheet are angled to match closely the slope of said parabolic curve at the mounting points; and wherein said QPT reflector is two halves of symmetrical QPT reflectors with junction in the middle at flat angle. 
     
     
         3 . The QPTPV apparatus of  claim 2  wherein said QPT reflector is a cylindrical trough reflector; wherein said cylindrical trough reflector is formed by identical three forming techniques as said QPT forming techniques matching circular curve parameters. 
     
     
         4 . The QPTPV apparatus of  claim 2  wherein said QPT reflector sheets are made of bendable rust-proof metal sheet, stainless metal sheet, plastic sheet, acrylic sheet, fiberglass sheet, synthetic or aluminum composite sheet; wherein said reflector sheets are coated with front mirror surface; and wherein said QPT reflector is made of rigid glass or acrylic sheet formed by heated bending with front or back mirror. 
     
     
         5 . The QPTPV apparatus of  claim 1  wherein said mounting arms of said linear solar panels is adjusted in height to spread out the sun rays evenly on said linear solar cells array in order to yield maximum output power. 
     
     
         6 . The QPTPV apparatus of  claim 1  wherein the tracker azimuth and elevation rotation activation is performed periodically; and wherein the pointing algorithm uses output power measurement as feedback in each period of the azimuth or elevation activations; and wherein maximum power is achieved by forward and backward stepping by azimuth or elevation stepping motors in two separate sequences; and wherein the azimuth and elevation stepping motors stay idle between activation periods. 
     
     
         7 . The QPTPV apparatus of  claim 1  wherein the mounting beams of said QPT reflectors on said 2-axes tracker are isosceles triangles in cross section with two base angles of mounting beams matching said parabolic curve slope at the mounting points. 
     
     
         8 . The QPTPV apparatus of  claim 7  wherein said mounting beams are made from elongated metal strip bended into isosceles triangle cross-section with open seam at the top vertex angle; and wherein the base of said mounting beams are attached on top of a cylindrical horizontal beam of said 2-axes tracker with axis of elevation rotation centered on said horizontal beam. 
     
     
         9 . The QPTPV apparatus of  claim 1  wherein the back of said linear solar panel is attached with multiple solar fans to cool down said passive radiators and said solar cells; and wherein said solar fans are constrained to the width of said linear solar panel. 
     
     
         10 . The QPTPV apparatus of  claim 1  wherein said active cooling flat pipes circulate coolant to a water tank with extended flexible piping for heat exchange inside said water tank; and wherein the coolant flow rate is controlled to desired combination of PV and water heating energy production; and wherein said coolant is water circulating said water tank directly. 
     
     
         11 . The QPTPV apparatus of  claim 10  wherein said linear solar panel is replaced with an insulated liquid heating pipe for the purpose of water heating only. 
     
     
         12 . A quasi-parabolic trough photovoltaic (QPTPV) solar energy apparatus comprising:
 an elongated quasi-parabolic trough (QPT) reflector consists of multiple concatenated QPT reflectors mounted on the frame of an 1-axis solar tracker;   multiple linear solar cells arrays consist of serial connected PV solar cells; wherein each said linear solar cells array is boxed in a rectangular linear solar panel; and wherein said linear solar panels are secured on adjustable height mounting arms which are perpendicular to said solar panels and said tracker frame; and wherein said linear solar panels are connected into one elongated linear solar panel; and wherein said linear solar cells arrays face said elongated QPT reflector at focal distance approximately;   wherein one or more selected said mounting arms of said elongated linear solar panel are connected to a linear actuators; wherein said linear actuators are fixed perpendicularly to said tracker frame; and wherein the extension of said linear actuator(s) adjust the height of said elongated linear solar panel;   wherein the remaining said mounting arms are inserted fittingly inside guiding tubes attached to the sides and gaps of said linear solar panels; and wherein said elongated linear solar panel is moved up or down along the guiding tubes with the activations of said linear actuator(s);   wherein a linear passive radiator array, or a circulating liquid cooling flat pipe is attached to the back side of each said linear solar cells array and secured inside said linear solar panel box for heat dissipation; and   wherein said elongated QPT reflector focus on and concentrate solar rays on said linear solar cells arrays to produce photovoltaic power and optionally, to produce heated water.   
     
     
         13 . The QPTPV apparatus of  claim 12  wherein said QPT reflector is made from a flat sheet of mirror reflector bended into desired parabolic curve by a QPT forming technique; wherein said QPT forming technique consists of 1) the linear span of said bended reflector matches closely to said parabolic curve linear span; 2) said reflector sheet width matches closely to said parabolic curve length between said linear span; 3) the mounting beams of said bended reflector sheet are angled to match closely the slope of the parabolic curve at the mounting point; and wherein said QPT reflector is two halves of symmetrical QPT reflectors with junction in the middle at flat angle. 
     
     
         14 . The QPTPV apparatus of  claim 13  wherein said QPT reflector sheets are made of bendable rust-proof metal sheet, stainless metal sheet, plastic sheet, acrylic sheet, fiberglass sheet, synthetic or aluminum composite sheet; wherein said reflector sheets are coated with front mirror surface; and wherein said QPT reflector is made of rigid glass or acrylic sheet formed by heated bending with front or back mirror. 
     
     
         15 . The QPTPV apparatus of  claim 12  wherein the tracker pointing algorithm uses output power measurement as feedback to 1-axis solar tracker rotation to achieve maximum output power; and wherein the mounting height of said linear solar panels are adjusted daily to accommodate solar orbit change using said output power measurement as feedback to achieve maximum power output. 
     
     
         16 . The QPTPV apparatus of  claim 12  wherein optional electromagnetic locks are installed on said guiding tubes to lock up said mounting arms and said linear solar panels between said linear actuator activation periods. 
     
     
         17 . The QPTPV apparatus of  claim 12  wherein the back side of said solar panel is attached with multiple solar fans for the cooling of said passive radiators and said solar cells; and wherein said solar fans are constrained to the width of said linear solar panel. 
     
     
         18 . The QPTPV apparatus of  claim 12  wherein said circulating liquid flat pipe is connected to a water tank with extended flexible piping for heat exchange inside said water tank; and wherein the coolant flow rate is controlled to desired combination of PV and water heating energy production; and wherein said coolant is water circulating said water tank directly. 
     
     
         19 . The QPTPV apparatus of  claim 18  wherein said linear solar panels are replaced with an insulated liquid coolant heating pipes connected for the purpose of heating water only. 
     
     
         20 . The QPTPV apparatus of  claim 12  wherein said linearly concatenated QPT reflectors is used for concentrated solar power (CSP) system reflectors; wherein said elongated linear solar panel is replaced by an insulated heating pipe carrying heated steam for electricity generation. 
     
     
         21 . A quasi-parabolic trough photovoltaic (QPTPV) system comprising:
 one or more curved trough reflector(s) mounted in the same orientation on the frame of a 2-axes or 1-axis tracker; wherein said curved trough reflector(s) is a QPT reflector, a cylindrical trough reflector or a curved trough reflector bending to a geometric curve closely; and   one or more linear solar cells array(s) consist of serial connected PV solar cells contained in a linear rectangular solar panel with passive or active heat radiation devices;   wherein said linear solar panel(s) are mounted on said 2-axes or 1-axis tracker frame with manual or automatic adjustable height mounting arms perpendicular to said solar panel(s); and   wherein said curved trough reflectors concentrate sun rays on said linear solar cells arrays to produce photovoltaic power and, optionally, to produce heated water.   
     
     
         22 . The QPTPV system of  claim 21  wherein said curved trough reflector is made from a flat sheet of mirror reflector bended into desired geometrical curve by a curved trough forming technique; wherein said curved trough forming technique consists of 1) the linear span of said bended reflector matches closely to said geometrical curve linear span; 2) said reflector sheet width matches closely to said geometric curve length between said linear span; 3) the mounting beams of said bended reflector sheet are angled to match closely the slope of said geometric curve at the mounting point; and wherein said curved trough reflector is two halves of symmetrical curved trough reflectors with junction in the middle at flat angle. 
     
     
         23 . The QPTPV system of  claim 21  wherein the combination technologies of 1) using said curved trough reflectors mounted on 2-axes or 1-axis solar tracker, 2) using said curved trough reflectors concentrating solar rays onto said linear solar cells array or heating pipe, 3) using output power measurement (or output thermostat temperature in water heating) as feedback to a maximum power pointing algorithm; wherein said combination technologies, or partial combination technologies, is used to save the cost of solar energy production. 
     
     
         24 . The QPTPV system of  claim 21  wherein said adjustment of solar panels height are used to spread out sun rays evenly on said linear solar cells array to achieve maximum solar output power. 
     
     
         25 . The QPTPV system of  claim 21  wherein multiple solar fans are attached on the back of said linear solar panel to speed up heat radiation; and wherein said solar fans are constrained to the width of said linear solar panel. 
     
     
         26 . The QPTPV system of  claim 21  wherein said active radiation device is doubled up as solar water heating device. 
     
     
         27 . The QPTPV system of  claim 21  wherein said linear solar panel(s) are replaced with insulated solar heating pipe(s) for the purpose of water heating only. 
     
     
         28 . The QPTPV system of  claim 21  wherein said curved trough reflectors mounted on 2-axis tracker are used for concentrated solar power (CSP) system with replacement of said elongated linear solar panel by an insulated linear solar heating pipe generating steams for turbine power generation.